Yak-9
is the third large family of WW-II Yakovlev's fighters. Development of the
Yak-7, it was very similar in appearance to its
predecessor. Two years of Yak-7 production and
service resulted in numerous changes in construction, equipment and armament.

Situation with metal supply in the USSR improved (both relocated
industry and import gained their momentum). More and more wooden parts were replaced
by light alloys. Saved weight resulted in improved performance - or could be used to
increase fuel capacity, bomb load, firepower. As a result, the Yak-9 was built in
number of modifications:

Yak-9 became the most built WW-II fighter in the
VVS inventory. In mid-
1944
three major modifications (Yak-9,
Yak-9T and
Yak-9D) outnumbered all other VVS
fighter types. Of total 22 major modifications 15 entered series production. Five engine
types were used (including modifications), six fuel tank variations, seven different armament
combinations and two types of special equipment. Wing used on Yak-9 fighters was of two major
types: mixed wood/metal and all-metal.

Appearance variations included removed chin oil cooler air intake,
added intake on the top of the engine,
reshaped and repositioned canopy, few variants of antenna mast. Yak-9 tank buster differed also
by gun barrel extended from the propeller spinner. Access hatch behind the canopy also could
be transparent, permanently sealed or deleted.

The Yak-9 could be not the best Soviet fighter built, and it was not a
record-setter. There were faster machines with better climb, better range or better armament.
But combination of all combat characteristics, including handling, ruggedness, stability,
simplicity and cheapness of production and service allowed the Yak-9 to play an important
role during WW-II.